Dental matrix instrument



1940- A. E HANSSEN 2,220,103

DENTAL MATRIX INSTRUMENT Filed Oct. 11, 1957 Fly. 2.

Fig.3.

Inventor Patented Nov. 5, 1940 UNITED STATES. PATENT -OFFICE DENTALMATRIX INSTRUMENT :Alfred E. 'Hanssen, Chicago, Ill. Application October 11, 1937, Serial No. 168,357

"4 Claims.

My invention relates to a novel construction of a matrix, the face of which is adaptable and adjustable, and the principal object of the invention is to provide a matrix that will serve as a means for inserting, confining, and uniformly condensing plastic dental filling materials into cavities located in the labial and buccal and lingual surfaces of teeth, and especially such cavities as are known to the dental professi'onby the name of gingival third cavities.

Another object of the invention is to provide a matrix face which will mold plastic filling materials so that when they set or harden the filling thus produced will have an outer surface which conforms to and reproduces the natural contour formerly possessed by the restored area or surface of the tooth.

Another object of the invention is to provide a matrixwhich will furnish the plastic filling materials with smooth and highly finished surfaces when said materials set or harden while in contact with the matrix face.

Another object of the invention is toprovide protection for plastic porcelain and cement filling materials from moisture in the mouth during the setting or hardening process.

Another object of the invention is to provide means for carrying plastic filling materials into dental cavities. v

For the purpose of illustrating my invention, I have shown in the accompanying drawing one form thereof, which is at present preferred by me, because the same has been found to give satisfactory and reliable results in actual prac-' tice. It is to be understood that the various instrumentalities of whichmy invention consists can be variously arranged and organized and that my'invention is not limited to the precise arrangement and organization of these instrumem talities as herein shown and described.

In describing my invention in detail, reference will be had to the accompanying drawing where in like characters denote like or corresponding parts throughout the several views, andin' which:

Figure l is a full view of the instrument with the arms 6 closed so as to give a definite contour to the matrix 5.

Figure 2 is a sectional view of the instrument showing the various parts in their relative positions and with the inner barrel 2 partly withdrawn to give the matrix 5 its natural form.

Figure 3 is a sectional view of the outer barrel I so as to show the arm operating slot II.

Figure 4 is a plan view of the matrix 5mm 55 one shape of face 22.

Figure 5 is a sectional view of the inner barrel 2.

Figure 6 is a side view and a partial section of the matrix rod ,I 0.

Figure 7 isa side view of arm 6.

Figure 8 is a plan view of the outer barrel I 5 showing slot II in which arms 6 move inward or outward as controlled by inner barrel 2 and spring I.

In these views, I indicates the outer barrel into which fits inner barrel 2. Thumb nut 3 seats in channel I3 of the inner barrel 2 and when engaged with thread 2 I said thumb nut 3 moves rod I longitudinally in channel 23. Through outer barrel I are set pivots 4 about which are pivoted arms 6. One end of spring I exerts pressure against tips 8 onarms 6 and the other end of spring 1 seats in channel I2 in inner barrel 2. Tips 8 rest against slots II in rod Ill and thus rod I0 is kept from turning and also, after being assembled, is kept within a limited range of longituclinal movement. Matrix consists of face 22 to which is attached screw 9 which engages with threads I8 in rod III. The threads I5 on inner barrel 2 engage with threads I6 in outer barrel I. When inner barrel 2 is turned counterclockwise bevel I4 contacts bevel I9 of arms 6 and causes them to move into slots II in outer barrel I, so that by these movements bevels of arms 6 will contact matrix 5 near its center. Knurl 24 on outer barrel I facilitates handling by furnishing a surface that is easily gripped.

The operation of the instrument is as follows:

As the matrix 5 will be supplied in various sizes, and its face '22 made of various materials and combination of materials, one is chosen which face 22, covers and fits most nearly the tooth area or surface to be filled. The peripheral outline form is trimmed to fit, with scissors. When placed upon the tooth the entire periphery of face 22 should rest upon the tooth structure ad- 40 jacent to the cavity margins. The fitted matrix is laid aside and the holder is next adjusted. This is done by turning thumb nut 3 clockwise thereby withdrawing rod ll] until its threaded end I8 is within barrel I and thus out of the way. By turning knurled end of barrel 2 as shown in Figure 1 counterclockwise, the beveled ends 2|] of arms 6 will be brought to meet. In this position ends 20 of arms 6 are placed over the cavity or tooth surface to be filled, and by moving inner barrel 2 clockwise end 20 of arm 6 are allowed to part until ends 20 rest upon the tooth structure adjacent to the cavity margins and those margins preferably which are located about the area of greatest width mesio-distally. Removing the instrument from the patients mouth, thumb nut 3 is now moved counterclockwise until end l8 of rod ll] projects beyond ends 20 of arms 6, thus allowing matrix to be attached to rod 10, screw 5' 9 being engaged by thread I8. Thumb nut 3 is then turned clockwise thereby drawing matrix 5 towards arms 6 until their ends touches face 22 of matrix 5. The instrument is now carried back to the mouth and face 22 of matrix 5 is placed over tooth area to be filled and held in the same position as when the detached matrix 5 was first fitted as to outline form. With the face 22 of matrix 5 thus in place on the tooth, thumb nut 3 is moved clockwise thereby drawing uniformly upon the convex surface of the tooth. With the instrument adjusted and the matrix adapted and adjusted as described, the intended filling material in a plastic condition is placed upon the concave surfaceof face 22 and carried into the cavity. Pressure is applied by theyoperator and the filling material is evenly condensed and adapted to all of the cavity walls and cavity margins. In case the gingival; (gum) cavity margin extends under the free margin of the gum, then the thin edge of the'matrix is slipped or placed under said gum margin, as previously fitted to do, and a close adaptation of the filling material is .thus caused along such gingival cavity margins. That action of my matrix is very advantageous in the manipulation of plastic filling materials and especially so where enamel or porcelain cements are used.

Said action is not obtainable by means commonly used. It is common practice to insert plastic filling materials by means of. spatulas and plugger shaped points and then, in case of porcelain cements, to cover the material with a strip 40 of Celluloid which is held in place by finger pressure. It is not possible thus to obtain an accurate adaptation of the filling material along all the cavity walls and margins andespecially so the gingival cavity margin, which is crescent shaped as to outline form, as well as being cut into and along a convex tooth surface. Due to these, circumstances, the commonly used method of filling such cavities results in a bulky surplus of material being' found about one or more margins of the filling. This surplus material must be removed by grinding after the filling material has set or hardened. My invention overcomes these objectionable features and will be of great practical value in the manipulation of all plastic materials used in connection with such cavities. Thus in the formation of inlay patterns made of wax, in inserting temporary stoppings, in the formation of silver amalgam fillings, and in the application of medicines and drugs to tooth surfaces, in all such manipulations my invention will be found very practical and useful.

While I have chosen to show the form of the holder and the arrangement of the barrels and nut illustrated, it will be evident that a great 65 variety of these might be made use of for obtainmatrix 5 closely against arms 6 until face 22 receives and forms a concave contour-Which rests ing part of the benefit of my invention and that other forms of combinations than the double barrel and pair of arms might be made use of to secure common adjusting and adapting means.

Having described my invention what is claimed is:

1. A dental matrix instrument comprising a matrix consisting of a thin deformable plaque provide with central holding means, a hollow handle, a rod adapted for longitudinal movement within the handle, and provided with means cooperating with the matrix-holding means to fix the matrix, at least one lever pivotally mounted on' the handle and engaging the marginal portion of the matrix plaque and means engaging the opposite end of the lever for forcing the matrix-engaging end of the lever in an adjustable matrix-deforming position whereby the matrix maybe conformed to any desired tooth surface. 2. A dental matrix instrument operative solely byathrusting force applied to its handle, comprising a thin normally fiat matrix plaque, flexi-. ble,; but tending tov return to flattened position, means centrally located on'said plaquefor attaching it to a thrust rod, a thrust rod attached thereto, a, handle and adjustable means coopere ating with the handle and thrust rod to secure the matrix plaque in an adjustably flexed position conforming to the curvature of a tooth surface. I

. 3. A dental matrix instrument comprising a matrix plaque provided with central attaching means a matrix holding rod with cooperating means for receiving; the attaching means, an outer barrel, an inner barrel for longitudinal movement within said outer barrel, cooperating means associated with said barrels for holding said barrel in fixed longitudinalrelation to each other, leverarms pivoted to said outer barrel and engageable with marginal portions of the matrix plaque, spring means seated on the inner barrel normally. urging the lever arms out of engagement; with the matrix, plaque, and adjustable means for'moving the matrix-holding rod longitudinally within said inner barrel wherebythe lever arms may be brought into adjustably controlled engagement with the matrix plaque to hold it conformed to a curved tooth surface.

4. A dental matrix instrument having a matrix conformable, to a tooth-surface independently, of

the tooth comprisinga flexible matrix plaque having the inherent property of returning to shape when flexing stress is removed, means central of the plaque for securing it to holding means, fingers associated with the holding means. for flexing the outer portion of the plaque to conform itto the desiredcurvatureof the tooth, and means for urgin the fingers into and out of engagement with the plaque, said last mentioned means including means engaging the plaque-holding means to adjust the plaqu'e to conform 'toa tooth surface and to maintain the plaque in adjusted "position; I a

' ALFRED E. HANSSEN. 

